Thermally driven micromechanical beam with piezoresistive deflection readout

This article reports on the fabrication and characterization of micromachined thermally driven micromechanical beam with piezoresistive readout for micro- and nanorobotic systems and advanced high speed scanning probe microscopy. The essential contribution of this paper is investigation of the actuating efficiency of an integrated cantilever microheater. To optimize the properties of the developed system we use finite element (analysis) modelling. Obtained theoretical and experimental results were proven using fiber interferometry in combination with electrical characterization of the piezoresistive deflection detector. We found out that the most efficient actuation position of the microheater on the beam is at the cantilever end. We have fabricated samples where the beam deflection was in range of 2 μm (for beam of length 550 μm). The smallest electrothermal driving power causing the deflection of 1 nm was estimated to be in the range of 8 nW.